I'm very sceptical about these additives which say that they do this & they do that. Quite a few years ago we did a test, on the Slick 50 that was meant to make your engine internals smoother & more wear resistant. We did measurements on the engine components before the engine was built, then did the test and stripped the engine to re-measure. Did the same to an engine which didn't have the Slick 50 added to do a back to back comparison. The result was that there was no difference to performance or engine wear.
I will have a chat with some of the engine test & development guys at work tomorrow to see what their thoughts are, IF[/] these products were that good, wouldn't the car manufacturers be clambering on the band waggon to promote it in their products ?
Also, alot of this it psychologica. You think you've put something in your engine that'll up the performance or fuel economy,99 times out of 100 it'll do nothing to it.
IMHO it's all mind games, and marketing.